OSPF，没有指定router id，router id没有选择loopback地址而是选择接口地址

eNSP模拟器中，配置OSPF，没有指定router id，router id没有选择loopback地址而是选择接口地址

[AR5]disp ip inter br
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 3
The number of interface that is DOWN in Physical is 1
The number of interface that is UP in Protocol is 3
The number of interface that is DOWN in Protocol is 1

Interface                         IP Address/Mask      Physical   Protocol  
GigabitEthernet0/0/0              10.10.0.2/24         up         up        
GigabitEthernet0/0/1              unassigned           down       down      
LoopBack0                         5.5.5.5/32           up         up(s)     
NULL0                             unassigned           up         up(s)
[AR5]disp ospf br

	 OSPF Process 2 with Router ID 10.10.0.2
		 OSPF Protocol Information

模拟器里面的路由用的AR1220，以为是模拟器的问题，又翻了翻这个型号的产品文档，是这样写的

router-id router-id为路由器的ID号。 缺省情况下，路由器系统会从当前接口的IP地址中自动选取一个最大值作为Router
ID。手动配置Router ID时，必须保证自治系统中任意两台Router ID都不相同。通常的做法是将Router
ID配置为与该设备某个接口的IP地址一致。

看来这个router id也不一定是优先选择loopback地址，还是要看产品